Police from Brockton, West Bridgewater, East Bridgewater and Bridgewater arrested three people on drug charges at 11:30 a.m. Thursday.

According to police a delivery of heroin was made to an undercover detective in Brockton by three suspects who drove to Prime Gas at 1666 Main St., where they were arrested.

Brockton Police Lt. Paul Bonanca said Rashad Williams, 21, of Brockton. Gildo Cardoso, 19, of Brockton and Gabriel Depina, 20, of Brockton, were charged with distribution of heroin with intent to distribute and conspiracy to violate the controlled substance act.

All three are expected to be arraigned Monday in Brockton District Court.